/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later,
 * or the Apache License Version 2.0.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package com.feilong.lib.javassist.compiler.ast;

import com.feilong.lib.javassist.compiler.CompileError;
import com.feilong.lib.javassist.compiler.TokenId;

/**
 * Expression.
 */
public class Expr extends ASTList implements TokenId{
    /*
     * operator must be either of:
     * (unary) +, (unary) -, ++, --, !, ~,
     * ARRAY, . (dot), MEMBER (static member access).
     * Otherwise, the object should be an instance of a subclass.
     */

    /** default serialVersionUID */
    private static final long serialVersionUID = 1L;

    protected int             operatorId;

    Expr(int op, ASTree _head, ASTList _tail){
        super(_head, _tail);
        operatorId = op;
    }

    Expr(int op, ASTree _head){
        super(_head);
        operatorId = op;
    }

    public static Expr make(int op,ASTree oprand1,ASTree oprand2){
        return new Expr(op, oprand1, new ASTList(oprand2));
    }

    public static Expr make(int op,ASTree oprand1){
        return new Expr(op, oprand1);
    }

    public int getOperator(){
        return operatorId;
    }

    public void setOperator(int op){
        operatorId = op;
    }

    public ASTree oprand1(){
        return getLeft();
    }

    public void setOprand1(ASTree expr){
        setLeft(expr);
    }

    public ASTree oprand2(){
        return getRight().getLeft();
    }

    public void setOprand2(ASTree expr){
        getRight().setLeft(expr);
    }

    @Override
    public void accept(Visitor v) throws CompileError{
        v.atExpr(this);
    }

    public String getName(){
        int id = operatorId;
        if (id < 128){
            return String.valueOf((char) id);
        }else if (NEQ <= id && id <= ARSHIFT_E){
            return opNames[id - NEQ];
        }else if (id == INSTANCEOF){
            return "instanceof";
        }else{
            return String.valueOf(id);
        }
    }

    @Override
    protected String getTag(){
        return "op:" + getName();
    }
}
